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33574c17 | 1 | /* Setup thread stack. Hurd/i386 version. |
581c785b | 2 | Copyright (C) 2000-2022 Free Software Foundation, Inc. |
33574c17 ST |
3 | This file is part of the GNU C Library. |
4 | ||
5 | The GNU C Library is free software; you can redistribute it and/or | |
ad2b41bf ST |
6 | modify it under the terms of the GNU Lesser General Public |
7 | License as published by the Free Software Foundation; either | |
8 | version 2.1 of the License, or (at your option) any later version. | |
33574c17 ST |
9 | |
10 | The GNU C Library is distributed in the hope that it will be useful, | |
11 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
ad2b41bf | 13 | Lesser General Public License for more details. |
33574c17 | 14 | |
ad2b41bf ST |
15 | You should have received a copy of the GNU Lesser General Public |
16 | License along with the GNU C Library; if not, see | |
5a82c748 | 17 | <https://www.gnu.org/licenses/>. */ |
33574c17 ST |
18 | |
19 | #include <stdint.h> | |
20 | #include <assert.h> | |
21 | #include <mach.h> | |
22 | ||
23 | #include <pt-internal.h> | |
24 | ||
25 | /* The stack layout used on the i386 is: | |
26 | ||
27 | ----------------- | |
28 | | ARG | | |
29 | ----------------- | |
30 | | START_ROUTINE | | |
31 | ----------------- | |
32 | | 0 | | |
33 | ----------------- | |
34 | */ | |
35 | ||
36 | /* Set up the stack for THREAD, such that it appears as if | |
37 | START_ROUTINE and ARG were passed to the new thread's entry-point. | |
38 | Return the stack pointer for the new thread. */ | |
39 | static void * | |
40 | stack_setup (struct __pthread *thread, | |
41 | void *(*start_routine) (void *), void *arg) | |
42 | { | |
43 | error_t err; | |
44 | uintptr_t *bottom, *top; | |
45 | ||
46 | /* Calculate the top of the new stack. */ | |
47 | bottom = thread->stackaddr; | |
48 | top = (uintptr_t *) ((uintptr_t) bottom + thread->stacksize | |
49 | + ((thread->guardsize + __vm_page_size - 1) | |
50 | / __vm_page_size) * __vm_page_size); | |
51 | ||
52 | if (start_routine != NULL) | |
53 | { | |
54 | /* And then the call frame. */ | |
55 | top -= 3; | |
56 | top = (uintptr_t *) ((uintptr_t) top & ~0xf); | |
57 | top[2] = (uintptr_t) arg; /* Argument to START_ROUTINE. */ | |
58 | top[1] = (uintptr_t) start_routine; | |
59 | top[0] = (uintptr_t) thread; | |
60 | *--top = 0; /* Fake return address. */ | |
61 | } | |
62 | ||
63 | if (thread->guardsize) | |
64 | { | |
65 | err = __vm_protect (__mach_task_self (), (vm_address_t) bottom, | |
66 | thread->guardsize, 0, 0); | |
67 | assert_perror (err); | |
68 | } | |
69 | ||
70 | return top; | |
71 | } | |
72 | ||
73 | int | |
74 | __pthread_setup (struct __pthread *thread, | |
75 | void (*entry_point) (struct __pthread *, void *(*)(void *), | |
76 | void *), void *(*start_routine) (void *), | |
77 | void *arg) | |
78 | { | |
79 | tcbhead_t *tcb; | |
80 | error_t err; | |
81 | mach_port_t ktid; | |
82 | ||
83 | thread->mcontext.pc = entry_point; | |
84 | thread->mcontext.sp = stack_setup (thread, start_routine, arg); | |
85 | ||
86 | ktid = __mach_thread_self (); | |
87 | if (thread->kernel_thread == ktid) | |
88 | /* Fix up the TCB for the main thread. The C library has already | |
89 | installed a TCB, which we want to keep using. This TCB must not | |
90 | be freed so don't register it in the thread structure. On the | |
91 | other hand, it's not yet possible to reliably release a TCB. | |
92 | Leave the unused one registered so that it doesn't leak. The | |
93 | only thing left to do is to correctly set the `self' member in | |
94 | the already existing TCB. */ | |
95 | tcb = THREAD_SELF; | |
96 | else | |
97 | { | |
98 | err = __thread_set_pcsptp (thread->kernel_thread, | |
99 | 1, thread->mcontext.pc, | |
100 | 1, thread->mcontext.sp, | |
101 | 1, thread->tcb); | |
102 | assert_perror (err); | |
103 | tcb = thread->tcb; | |
104 | } | |
105 | __mach_port_deallocate (__mach_task_self (), ktid); | |
106 | ||
107 | tcb->self = thread->kernel_thread; | |
108 | ||
109 | return 0; | |
110 | } |